As you'll no doubt be aware, Qualcomm currently enjoys a stranglehold on processing hardware inside Windows Phone handsets. Its Snapdragon chip stars in both Microsoft's original and updated chassis spec for the platform, but its hegemony may soon be coming to an end. STMicroelectronics (the ST in ST-Ericsson) boss Carlo Bozotti is cited by Forbes as saying that Nokia will use ST-Ericsson hardware to power at least some of its Windows Phones. The dual-core U8500, a long-time Nokia favorite, is touted as the first such system-on-chip to appear, with its successors helping to populate Nokia's expansive WP lineup in 2012. The only intel we've had so far on Nokia's initial handsets for the new OS revolved around Qualcomm-based devices, so even if ST-Ericsson is indeed going to infiltrate the Windows Phone ecosystem, it doesn't look likely to be among the very first Nokias out of the gate.
